Hi razzle51
Burning feet here also - currently middle of summer where I am so at its worst. Can't tell you too much about it as I'm still trying to find out myself. I have an endocrine disorder (cause: auto-immune) which causes all sorts of symptoms so it may be part of that.
Burning feet as a symptom has also been linked to: Sjogrens Disease, Peripheral Neuropathy and Vitamin B deficiencies (amongst other things), so there could be any number of reasons.
Getting relief: medically so far I have found no solutions (I don't think the doc's really get how bad it is) but I get some temporary relief from basic things like sitting with feet in a bucket of cold water. To sleep at night I wrap a freezer block (like you put in a "cooler, ice chest, chilly bin" - depending on where you're from) in a hand towel and put it between my feet - will last most of the night.
Good luck finding relief - appreciate anyone with more info re diagnosis or treatment if they could post it please.